Radio receiver



Oct. 3, 1939. F. J. HOOVEN 2,175,025

I RADIO RECEIVER Filed July 16, 1936 4 Shoots-Sheet 2 IN V EN TOR.

ATTORNEY Oct. 3, 1939. F. J. HOOVEN 2,175,025

RADIO RECEIVER Filed Jt lly 16, 1936 4 shocks-Sheet 4 um 150K Jew/yew BY Q d ATTORNEY Fin. 8

Patented Oct. 3, 193 9 UNITED STATES PATENT OFFICE RADIO RECEIVER Frederick J. Hooven, Dayton, Ohio Application July 16, 1936, Serial No. 90,991

16 Claims.

My invention relates broadly to radio receivers and more specifically to a construction of radio compass receiver particularly adapted for operation on aircraft.

One of the objects of my invention is to provide a. construction of radio compass receiver which. may be initially adjusted for operation on aircraft and thereafter substantially s'ealed against tampering or maladjustment for insuring precision operation of the apparatus.

Another object of my invention is to provide a construction of radio compass receiver in which trimmer adjustment of the circuits of the receiver is permitted after the receiver has been adjusted to a. high degree of precision and sealed within a substantially fluidtight casing.

Still another object of my invention is to provide a construction of radio compass receiver in which circuit connections for the signaling circuits are brought out through pin contacts projecting through the housing of the receiver for coaction with a junction box having sets of aligned coacting contact devices adapted to establish connection with the contact pins, the junction box being attachable to the receiver only after the receiver has been completely sealed.

A further object of my invention is to provide a construction of radio compass receiver in which exterior circuit connections can be established with the internal circuits of the radio compass receiver only after the radio compass receiver has been scaled and whereby it is essential to remove the external circuit connections before unsealing the radio compass receiver.

A still further object of my invention is to provide a construction of radio compass receiver in which the operating circuits are sealed within a moisture-proof housing to which external power supply circuits are connected through filter devices carried within a detachable junction box connectible with pin terminals extending from the radio receiver after the radio'reoeiver has been sealed within the housing.

Another object of my invention is to provide a,

construction of cast metal housing for radio receivers in which a multiplicity of inwardly directed ribs or guides is cast integrally with'the material of the housing serving to guide the radio receiver chassis into and out of the housing.

Still another object of my'invention is to provide a construction of cast metal housing for radio receivers in which a compressible gasket is interposed between the inner face of the front panel and periphery of the cast metal housing and is compressible under the force of a retaining screw member extending through the housing and through the chassis of the radio receiver within the housing to secure a means engaging the rear wall of the housing for insuring the moisture-tightclosure of the radio receiver within the housing. I

A further object of my invention is to provide a simplified construction of filter containing junction box adapted to be aligned with a plurality of outwardly projecting contact pins and to establish connection therewith only in a predetermined manner for completing exterior circuit connections to the internal circuits of the radio receiver.

A still further object of -my invention is to provide a detachable connection means on the exterior wall of a junction box which is in turn detachable with respect to a plurality of contact pins projecting from a radio receiver chassis within a protective housing.

Still another object of my invention is to provide means for establishing a radio frequency feed connection between the circuits of a radio compass receiver substantially sealed within a moisture-proof housing with a radio frequency feed connection external to the housing.

Other and futher objects of my invention reside in an arrangement for housing a radio compass receiver and remotely driving the radio receiver while the parts thereof are substantially sealed within a moisture-proof casing as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the radio compass receiver sealed within the special housing of my invention; Fig. 2 is a perspective view showing the cast metal housing of my invention with the radio compass receiver removed therefrom; Fig. 3 is a perspective view of the radio compass receiver and showing the chassis thereof removed from the protective housing; Fig. 4 is a perspective view of the radio compass receiver sealed within the protective housing and showing the housing broken away at the top and side walls thereof to illustrate the construction of longitudinally extending guiding ribs which I employ interiorly of the cast housing of the radio compass receiver; Fig. 5 is an enlarged cross-sectional view showing the detachable junction box which I provide for the radio compass receiver and illustrating the housing and chassis of the radio compass receiver in foreshortened construction showing the manner in which the housing is sealed when the junction box is in operating position; Fig. 6 is a view showing the manner in which the junction box is removed from the rear wall of the radio compass receiver for breaking the external circuits before the receiver chassis may be removed from the housing; Fig. 7 illustrates the circuit connections for the filter devices carried within the junction box and the manner of associating the electrical connections which extend from the junction box to the control box adjacent the pilot's position, the visual course indicators adjacent the pilot's position, the marker beacon indicator, the marker beacon receptor. the high and low voltage power supply units, and the directional loop antenna used in the radio compass receiver; and Fig. 8 diagrammatically and schematically illustrates the circuit arrangement of the radio compass receiver and showing the manner in which the circuits thereof terminate at the pin contactswith which the contact devices carried by the junction box establish electrical connection.

My invention is directed to a construction of radio compass receiver particularly intended for aircraft where a high degree of precision and simplification in operation is essential to safety. I so construct the radio compass receiver that all the operating circuits thereof may be sealed within a substantially moisture-proof housing. The circuits are tested and adjusted with a high degree of precision before the chassis is inserted into the protective housing in which the apparatus is substantially sealed against moisture. The radio compass receiver properly sealed within the housing may be remotely located in the fuselage of the aircraft and connected with cooperative parts of the radio compass receiver through flexible conduits and through flexible drive means for remotely controlling the radio compass receiver from the pilots position. The circuits of the radio compass receiver are brought out to outwardly projecting contact pins carried by an insulated panel. A removable junction box carrying filter units for preventing the introduction of interference in the power circuits of the receiver, carries a multiplicity of coacting contact devices adapted to establish connection with the contact pins connected with the circuits of the radio receiver. I provide a retaining screw member projecting through the front portion of the panel of the ridio receiver, through the chassis of the radio receiver and engaging the rear wall of the cast metal housing for sealing the front portion of the radio receiver chassis through a peripheral gasket with respect to the periphery of the cast metal housing of the radio receiver. The internal circuits of the radio compass receiver having been once adjusted may, therefore. be sealed against tampering or maladjustment. Due to heat created by the operation of the tubes within the radio compass receiver, I provide an air conditioner containing hygroscopic material which is maintained in the only path for the ingress and release of air which remains between the interior of the radio compass receiver and the atmosphere. This feature is important because or the variation in temperature, pressure, and humidity conditions, to which the'radio compass receiver is subjected in aircraft operation.

The cast metal housing is provided with a pinrality of inwardly directed longitudinally extending ribs which serve as guides directing the .movement of the radio receiver chassis into and out of the housing.

Connections for a flexible drive shaft are provided adjacent the front portion of the chassis of the radio compass receiver whereby the tuning of the receiver may be remotely controlled from the pilots position. The removable junction box wholly covers the securing means on the rear of the housing by which the front panel portion is sealed with respect to the housing. Accordingly, the housing must be sealed before the junction box is placed in position. The housing cannot be unsealed until the junction box is removed from the housing thereby disconnecting the external circuits from the internal circuits of the radio compass receiver.

The junction box is provided with a multiplicity of separable connectors which connect through flexible conduits with the circuits of the control box adjacent the pilots position, the course indicating meters adjacent the pilots position, the radio frequency feed circuits. and the power supply and marker beacon receptor circuits. I have found the radio compass receiver of my invention highly effective and efficient in operation.

While one of the special features of my invention is to provide a sealed radio compass receiver which cannot be tampered with or maladjusted after installation in aircraft, nevertheless, I provide a construction permitting adjustment of the trimmers in the antenna circuit of the receiver after installation on aircraft. Such adiustment of trimmers is essential in order to insure resonance in the receiver in operation on antenna systems which may differ in capacity characteristics on different aircraft. For this purpose, I provide removable plugs in one wall of the metallic housing through which adjustment of the trimmers may be made, the plugs being removed and restored to allow the adjustment of the trimmers by means of a tool projected through the casing.

Referring to the drawings in detail, reference character I indicates the cast metal housing of the radio compass receiver of my invention. The front panel 2 of the radio compass receiver is secured against the peripheral edge la oi casing 1 with gasket ll providing a sealing means therefor. The front panel 2 has a housing 8 projecting therefrom. The housing 9 provides an enclosure for the condenser drive and motor for the gang switch of the radio compass receiver. There is a panel H serving as a closure for the housing 8 with a gasket l2 between the panel H and the peripheral edge of the housing 9 which serves to seal the condenser drive and motor for the gang switch against entry of moisture. The panel H is removably secured to the housing 9 by means of screw members indicated at N. There is a recess in panel II which I have indicated at II which serves as a pocket for receiving the headed end of the retaining screw member indicated at l. The head on the retaining screw member 4 is indicated at II in Fig. 5, and is shown as having a polygonal socket i8 therein for receiving the tool by which the retaining screw member I may be revolved in assembling or disassembling the parts of the casing as will be hereinafter described in more detail. The retaining screw member I extends through an aperture I! in panel I and through aligned aperture in the rear wall of the casing l which I have indicated at [8. The chassis of the radio compass receiver, shown more particularly in Fig. 3, is provided with a rear wall structure indicated generally at il't rough which a sleeve member extends, pro fling a passage for the retaining screw member 4 which also passes through the aperture II in the rear of easing I. The end of the retaining screw member 4 is screw-threaded as indicated at 2I for receiving the retaining nut 22 which may be which shows the threaded end 2I of the retaining screw member 4 projecting beyond the rear wall structure I9 of the radio compass receiver. The radio compass receiver includes the radio frequency coil and switch assembly structure indicated as retained within the shielded chassis 23. The variable condenser system is indicated as being housed generally within frame structure 24 with adjusting means for the trimmer condensers shown generally at 25. The tube complement is shown generally as supported by the chassis at 26 with a horizontally extending member 21 serving as means for maintaining the alignment of theseveral tubes. The housing for the tuned audio frequency filta' may be seen at 26. in Fig. 3. The other parts of the radio compass receiver are compactly mounted in the chassis which houses the intermediate transformers, the headphone transformer, the fixed condenser housings, the coil housings, shields, the meter coil transformer, and the other elements making up the radio compass receiver. The horizontally extending member 21 projectsover the chassis of the receiver forming a protective plate, represented generally at 29. Relatively flat surfaces are presented over each of the side walls of the radio compass receiver to provide means for guiding the radio compass receiver into position within the cast metal housing I.

As shown more particularly in Figs. 2 and 4,- the cast metal housing I of the radio compass receiver is provided with a. multiplicity of interiorly disposed longitudinally extending ribs 30. The ribs 30 extend parallel with the side walls of the cast metal housing I. The ribs 30 are directed inwardly and serve as guides on which the receiver chassis is readily moved into and out of the cast metal housing I. At each position of contact between the receiver chassis and the ribs 30, the chassis of the receiver is relatively flat. That is to say, the relatively fiat top and, bottom portions of the receiver chassis directly engage the inwardly directed ribs 30 in the top and bottom of the cast metal housing I. At

- opposite sides of the radio compass receiver, the

intermediate supporting plate 3| provides a projecting edge 32 which coacts with an aligned projecting edge 33 of the chassis of the receiver to provide guiding means with respect to one of the aligned ribs 30 in the side wall of the cast metal housing I. The intermediate supporting plate 31 projects in a direction opposite .from the projection indicated at 3'2 and is directed downwardly as shown at 34, coacting with an inwardly projecting rib 30 in the opposite side wall of the cast metal housing I, serving as a guide for directing the receiverchassis into and out of the cast metal housing I. That is to say, the radio compass receiver chassis is so formed that a flat abutment is provided on each side thereof for coaction with the inwardly directed parallel extending ribs 30 within the cast metal housing I, facilitating the movement of the chassis into and out of the housing.

The rear wall of the chassis indicated at is is apertured at 35 and constitutes a frame across which the insulated panel 36 extends. The insulated panel 36 is secured in position with respect to the end wall of the receiver chassis by means of a frame member 31 through which screw members 38 extend and are engaged in the end wall of the chassis of the receiver. The insulated panel 36 provides mounting means for the sets of rearwardly extending contact pins 5. The frame 31 defines a rearwardly extending projection on the rear of the chassis of the radio receiver adapted to be aligned with an inwardly projecting flanged aperture 39 in the end wall of the cast metal housing I. The aperture 39 is bounded by means of an inwardly directed peripheral flange 40 shaped to conform with the contour of the rearwardly projecting frame 31. Accordingly, the radio receiver chassis may be readily moved into the cast metal housing I with the frame 3-1 and insulated panel 35 fitting within the aperture defined by the inwardly extending peripheral flange 40. with the contact pins 5 projecting exteriorly of the rear wall of the housing I.

Electrical circuit connections extend from the receiving apparatus within the chassis to the sets of contact pins 5 through conductors which I have indicated generally at 4 I.

Referring to Fig. 8, the insulater panel 36 shows the sets ofpins 5 thereon constituting the group of contact pins illustrated in perspective view in Fig. 3. For purposes of explaining the manner in which the group of contact pins ,5 coact with the contact devices 1 which are carried by the insulated support 42 mounted within junction box 3, I have applied reference characters I'2Ii' to the contact pins on panel 36 as illustrated in Fig. 8. In Fig. '7, the coacting contact devices indicated at 1 have been correspondingly numbered as I '20".

Referring to Fig. 8, the housing I has been designated in dotted lines as effectively enclosing the circuits .of the radio compass receiver. The non-directional antenna employed with the radio compass receiver has been designated at 43. The frequency selector system is indicated generally at 44 including coupling means 45 and 46 for the circuits of high frequency amplifiers 48 and 49. The multi-electrode electron tube 41 operates as a converter and supplies energy to the intermediate frequency amplifier stage 50. A double diode tube 5I is provided coupled to the intermediate frequency amplifier 50. Connections are taken from the double diode tube 5| to the audio frequency amplifier tube 52 from which the energy is sup-plied to two different channels, one channel including electron tube 53 and the other channel containing electron tube 54. The output circuit of tube 54 connects through transformer 55 to contact pins 1' and 8'. The output circuit of tube 53 connects through transformer 56 to contact pins I1 and I3.

Referring to Fig. 7, it will be observed that the coacting contact devices in the group of contact devices 1 and 8" connect with the leads extending to the control box 51. Likewise, contact pins I1 and I8 register with coacting contact devices I1" and I8" which lead to circuit connections extending to the control box 51 adjacent the pilot's position.

The visual course indicators for the radio compass have been indicated at 58 and 59 connected through conduit 60 with junction box 3. The socket receptacles on the junction box 3 which provide detachable connections for the cables in the conduits leading from the junction box have been illustrated in Fig. 4 at 6, 6|, 62, 63 and 64. The detachable connection between junction box 3 and control box 51 is efiected through the detachable plug receptacle indicated at 6 by means of a coacting socket head carried by conduit 65 through which the conductors pass to the control box 51. The conduit 60 has a socket head thereon which contains the flexible wires leading to the course indicators 58 and 59 and to the marker beacon flash indicator 66. The socket head on conduit 60 establishes connection with the receptacle 6! on junction box 3. The connections leading from the junction box 3 to the power supply unit terminate in the receptacle 62 with which a socket head carried by conduit 61 is adapted to be removably connected. Conduit 61 contains the conductors which lead to the power supply unit which I have shown generally at 68. The power supply unit includes the high voltage source 69 for the plate circuits and is connected through filter units which I have designated generally at 10. The low voltage source II for the cathode circuits connects through filter units which I have designated generally at 12 with the terminal connector indicated generally at 13. The power supply unit 68 is also provided with a terminal board 14 through which connections are made for supplying power to the marker beacon receptor shown generally at 15 by means of coacting connector 16. Connections are also taken from the output of the marker beacon receptor through coacting connectors l6 and M through terminal board 13 and conduit 61 with receptacle 62 on junction box 3.

Radio frequency feed connections are provided through receptacles 63 and conduit l! with the directional antenna unit which I have indicated generally at 18. Bias potential is supplied through receptacle 64 to the conduit I have indicated generally at 19. 7

Within the. junction box 3, I provide filter condensers 80 and filter chokes 8! which serve to prevent interference picked up on the external circuits from entering the radio compass receiver. I have designated the pentagrid modulator tubes which are connected to the directional receiving system at 82. These tubesare connected to a suitable selective tuning system shown at 83 which is adjustable simultaneously with the adjustments of the tuning circuits of the non-directional receiver. The oscillator tubes controlled by the modulator tubes 82 are indicated generally at 84. The outputs of the oscillator tubes being connected to contact pins II and 6' coacting with contact devices I l" and 6 connected through leads extending through socket terminals 6|, conduit 66', with the visual course indicators 58 and 59. The remote control driving motor which is housed within the projecting portion 9 of the casing I is shown generally at 85 connected through leads extending to contact pins l5 and i which coact with contact devices l" and i0 which connect through leads and socket receptacle 6 and from thence through conduit 65 to the control box 51 from which the tuning of the radio compass receiver is controlled. i

For convenience, I have indicated all of the heater circuits for the several tubes at 86 and 81 connected to the power supply circuits through the contact pins l' and IS in the group of contact pins 5.

In order to insure the alignment of the contact devices 1 carried by the insulated support 42 with the contact pins 5, I arrange a projecting plug 88 normal to the rear wall of the receiver chassis l9. The plug 88 is provided with a substantially conical shaped end adapted to fit into a correspondingly shaped aperture 89 in insulated support 42. Plug 88 is provided with a tool engaging socket 99 facilitating the mounting of the plug 88 on the rear wall l9 oi?v the chassis of the radio receiver. A screw-threaded end 9i on plug 88 engages a correspondingly screw-threaded aperture in the rear wall l9 of the chassis of the radio receiver. The junction box 3 cannot be secured in position until socket 89 is properly aligned with plug 88. Thereafter, the contact devices I may be moved into connected position over the group of pins 5. As heretofore pointed out, the junction box 3 contains the condensers 80 and choke coils 8| which prevent entrance of interfering currents picked up on the external circuits into the sealed radio receiver housing. The junction box 3 is aligned at its periphery with a gasket 92 which seals the interior of the junction box against thev entrance of moisture. Removable screw members 93 are provided for locating thejunction box in position. The screw members 93 are screw-threaded at the ends thereof and engage'screw-threaded apertures in housing I as indicated at 94. The sockets which engage the receptacles 6, 6|, 6!, 68 and 64 are plugged into the receptacles after the junction box is secured in position adjacent the rear of the housing I.

The flexible drive for the tuning control of the receiver extends through bushing 95 in the projecting portion 9 ofv the housing I The air conditioner filled with hygroscopic material is indicated at 96 connected with the front panel 2 and providing a passage into the interior of the sealed housing I.

While the housing of the radio compass receiver is sealed against moisture, I provide means for adjusting the antenna coil trimmers as indicated by the removable plugs 91 and 58 screwthreaded into apertures 91a and 98a in the side wall of housing i. The apertures 91a and 98a are aligned with the antenna coil trimmers on the chassis of the radio receiver when the radio receiver is moved to final position within the housing. Final adjustment of the radio compass receiver may, therefore, be made for variations of antenna capacity encountered on the aircraft when the receiver isinstalled.

To facilitate maintaining of the radio compass receiver, I cast on the exterior of housing' I the symmetrically disposed -feet 99 which support the complete receiver. The feet 99 project from the base of the housing I and may be equipped with shock-proof pads by which the receiver is resiliently mounted.

I have found the radio compass receiver oi" my invention'highly practical in manufacture and I realize that 1. A radio receiver comprising a metallic housing, a radio receiver chassis insertable into and removable from said metallic housing, a panel carried by said radio receiver chassis and engageable through sealing means with the peripheral edge of said metallic housing, a panel structure oilfset from and extending in a plane substantially parallel to the aforesaid panel and a retaining screw operative from the front of said panel structure and extending through said panel and chassis and engaging the rear wall of said receiver chassis in substantially sealed position within said metallic housing.

3. A radio receiver comprising in combination with a metallic housing, a radio receiver chassis insertable into and removable from said metallic housing, a panel connected with said chassis, sealing means disposed between the rear wall of said panel and the front peripheral edge of said metallic housing, a walled enclosure extending from the front of said panel, a panel structure extending across said walled enclosure, means countersunk into said panel structure and extending therethrough and through said panel and chassis for securing said panel structure in sealed engagement with the peripheral edge of said metallic housing, and means carried by the interior walls of said metallic housing for guiding said radio receiver chassis into and out said metallic housing.

4. A radio receiver comprising in combination with a metallic housing, a radio receiver chassis insertable into and removable from said metallic housing, a panel connected with said chassis, sealing means disposed between the rear wall of said panel and the front peripheral edge of said metallic housing, a walled enclosure carried by said panel, a panel structure closing said walled enclosure, said panel structure having an inwardly extending pocket, means for securing said panel in sealed engagement with the peripheral edge of said metallic housing, comprising a headed connecting member secured in the pocket in said panel structure and extending through said panel and said chassis and secured through the rear wall of said housing, and a plurality of inwardly directed ribs carried by the interior walls of said metallic housing and engageable with said radio receiver chassis for guiding said radio receiver chassis into and out of said metallic housing.

5. A radio receiver comprising a metallic housing, a radio receiver chass s adapted to be inserted into or removed from said metallic housing, a panel structure connected with said radio receiver chassis, sealing means interposed between the rear wall of said panel structure and the peripheral edge of said metallic housing for substantially sealing said chassis within said housing, a panel carrying contact pins mounted on said chassis, the rear wall of said housing being apertured to allow the passage of the contact pins carried by said last mentioned panel for forming terminals for the circuits carried by said radio receiver chassis, means substantially sealing said housing between the apertured portion thereof and said last mentioned panel and means exteriorly of said housing for establishing connection with said contact pins.

6. A radio receiver comprising a metallic housing, a radio receiver chassis adapted to be inserted into or removed from said metallic housing, a panel structure connected with said radio receiver chassis, sealing means interposed between the rear wall of said panel structure and the peripheral edge of said metallic housing for substantially sealing said metallic chassis within said housing, an insulatedpanel carried on the rear of said radio receiver chassis, a multiplicity of contact pins projecting rearwardly from said panel and forming circuit terminals for the circuits carried by said radio receiver chassis, the rear wall of said metallic housing being apertured to allow the passage of said contact pins, means engaging the exterior of the rear wall of said housing for establishing connection with said contact pins and means extending between said metallic housing and said chassis peripherally about said panel for sealing said metallic housing when said chassis is in position therein.

7. A radio receiver comprising a metallic housing, a radio receiver chassis adapted to be inserted into or removed from said metallic housing, a panel structure connected with said radio receiver chassis, sealing means interposed be-- tween the rear wall of said panel structure and the peripheral edge of said metallic housing for substantially sealing said chassis within said metallic housing, an insulated panel carried on the rear of said radio receiver chassis, a multiplicity of contact pins projecting rearwardly from said panel and forming circuit terminals for the circuits carried by said radio receiver chassis, the rear wall of said metallic housing being apertured to allow the passage of said contact pins, means extending peripherally about the apertured portion of the rear wall of said housing for establishing a sealing connection with respect to the rear of the chassis when the chassis is moved to operative position within said metallic housing and a removable terminal block detachably connectible with the rear wall of said metallic housing for establishing detachable connection with said contact pins and providing means for establishing connection between exterior circuit means and the circuits carried by said radio receiver chassis.

8. A radio receiver comprising in combination, a metallic housing, a radio receiver chassis adapted to be inserted into and removed from said metallic housing, a front panel structure connected with said radio receiver chassis and adapted to establish sealing connection with the said peripheral edgewall of the metallic housing, an insulated panel carried by the rear wall of said chassis, contact pins projecting rearwardly from said panel and connected with the circuits of the receiving 4 establishing connection therewith, means for completing external circuit connections with the contact devices carried by said junction box and means carried by said junction box and connected with the contact devices therein for preventing said panel and connected with the circuits oi. the

receiving apparatus carried 'by said radio receiver chassis, a detachable junction box, means for detachably connecting said junction box with the rear wall of said metallic housing, contact devices carried by said junction box and adapted to be aligned with the contact pins projecting from said panel for establishing connection therewith, separately detachable connecting means exterior to said junction box for establishing connection between said external circuits, said contact devices, and the contact pins with the circuits of the apparatus carried by said radio receiver chassis and means carried by said junction box and connected with the contact devices therein for preventing transfer of interfering currents from the external circuit connections to the circuits carried by said radio receiver chassis.

10. A radio receiver comprising a metallic housing, a radio receiver chassis adapted to be inserted into or removed from said metallic housing, a panel structure connected with the radio receiver chassis and adapted to establish sealing connection with the front peripheral edge of said metallic housing, means extending through said front panel structure and passing through said radio receiver chassis and engaging the rear wall of said housing for securing said radio receiver chassis in substantially sealed position within said housing, an insulated panel structure carried by the rear wall of said chassis immediately adjacent the position where said last mentioned means passes through said chassis, a plurality of contact pins carried by said insulated panel structure and projecting rearwardly therefrom and forming circuit terminals :lor the circuits. of said radio receiver chassis, the said first mentioned means and the said contact pins extending through perforate portions of the rear wall of said housing,,a junction box detachalcly connectible with the rear wall of said housing, contact devices carried by said junction box and adapted to establish electrical connection with the contact pins projecting from said insulated panel, said junction box wholly covering the fas=- tening means which operates to secure said first mentioned means with respect to the rear wall of said housing, means for establishing electrical connection with the contact devices in said Junetion box and means carried by said junction box and connected with said contact devices for pre-- venting transfer oi. interfering currents from said contact devices to said contact pins.

'1i.A radio receiver comprising a metallic housing a rear wall containing a perforate portion, a radio receiver chassis lnsertable into and removable from said metallic housing, a panel structure connected with said chassis and operating to establish sealing connection with said metallic housing, a retaining screw extending through said panel structure, through said radio receiver chassis, and through the rear wall 01 said housing, screw means engageable with the-end or said retaining screw for securing said radio receiver chassis in position within said metallic housing, pin terminals projecting from the rear 0! said radio receiver chassis through the perforate portion of a rear wall or said metallic housing, a Junction box having contact devices engageable with said contact pins and adapted to wholly cover said screw device when in position with respect to the rear wall of said metallic housing, detachable connector means carried by said junction box tor completing detachable electrical connections between external circuits and the circuits carried by said radio receiver chassis and means mounted in said junction box and connected with said detachable connector means for preventing the transfer of interfering currents from the external circuits to the circuits carried by said radio receiver chassis.

12. A radio receiver comprising a housing, a chassis insertable into and removable from said housing, a panel structure connected with said chassis, means for substantially sealing said chassis within said housing, connecting means for the circuits carried by said chassis extending through one wall of said housing, a junction box detachably connectible with the said wall of said housing, said junction box carrying coacting contact devices operative to establish electrical connection between external circuits and the circuits carried by said radio receiver chassis and connected with said connecting means, and interierence prevention means carried by said junction box for preventing the transfer of interfering currents from the external circuit connections to the internal circuits carried by said chassis.

13. In a radio receiver, a housing, a chassis removably mounted within said housing, a plurality or terminal means carried by said chassis and projectible through one wall of said housing, a removable junction box, a plurality of contact devices carried by said removable junction box, means coordinating and aligning said junction box with said housing for insuring interconnection between said coacting contact devices and said terminal means on said radio receiver chassis, and means carried by said junction box and interposed between external circuit connections connected therewith and the internal circuits carried by said chassis i'or preventing the transfer of interfering currents from the external circuits to the circuits interlorly oi. said chassis.

14. A radio receiver comprising a closed metallic housing, a radio receiver chassis adapted to be inserted into or removed from said closed metallic housing, a panel structure connected with said radio receiver chassis, and engageable with the peripherai portion of said closed metallic housing when said radio receiver chassis is moved into said closed metallic housing, on hi sulated panel carrying contact pins mounted with respect to said chassis and projecting normal to said chassis and forming terminals for the circuits carried by said chassis extending beyond the limits of said chassis, and a removable and replaceable multiple contact connector device and flexible cable system exteriorly of said closed metallic housing for establishing through the multiple contacts said connector device, quick detachable connect n with said contact pins and completing electri circuits with the circuits carried by said ran receiver chassis.

15. A radio receiver comprising a closed metallic housing open at one end to receive a radio receiver chassis, a radio receiver chassis substantially conforming to the internal contour of said housing and adapted to be inserted into or removed trom said closed metallic housing through the open end thereof, a panel structure connected with said radio receiver chasis and engageable with the peripheral portion of said closed metallic housing when said radio receiver chassis is moved into said closed metallic housing, and means extending through said panel along a substantially horizontal axis coincident in direction with the line of direction in which said radio receiver chassis is removable and returnable with respect to said closed metallic housing, said means having an actuator on one end and means on the other end engageable with the interior remote end of said closed metallic housing for maintaining said radio receiver chassis in timed operative position within said closed metallic housing.

18.Aradioreceiveraclossdmego tallichousingopenatoneendtoreceivearadio receiver chassis, a radio receiver chamis substantially conforming to the internal cmtour 0! said housing and adapted to be inserted into or removed from said closed metallic housing through the open end thereof, a panel structure connected with said radio receiver chassis and engageable with the peripheral portion of said closed metallic housing when said radio receiver chassis is moved into said closed metallic housing, and means extending through said panel and through said radio receiver chassis and along a substantially horisontal axis coincident in direction with the line of direction in which said radio receiver chassis is removable and returnable with respect to said closed metallic housing, said means being engageable with said closed metallic vhousing tor maintaining said radio receiver chassis in timed operative position within said closed metallic housing. 

